1. Field of the Invention
The present invention relates to a method of and an apparatus for processing linework image data representing a linework image to produce a supplementary area adjacent to the linework image.
2. Description of the Related Art
Shadowing in image processing is a technique to add a shadow area to linework images such as characters and illustrations to increase their visual impact. A conventional shadowing process shifts a target linework image in parallel by a small distance to form a supplementary area adjacent to the target linework image. The supplementary area is then shaded or colored to make the shadow area. FIG. 1A shows a linework image accompanying a shadow area formed by the conventional process. As shown in FIG. 1A, a shadowed linework image includes an original linework area A2 and a shadow area A1. The original linework area A2 is always laid over the shadow area A1 to make the shadow area A1 seem to be a real shadow.
Since the conventional shadowing process simply forms a shadow area by the parallel movement of the target linework image, the shadow area cannot give a three-dimensional effect such as that shown in FIG. 1B. There are presently no methods and apparatus available for forming a supplementary area A3 such as shown in FIG. 1B. Once formed, the supplementary area A3 can be easily shaded or colored to make a shadow area giving a three-dimensional effect.